Pump



D. N. HAPKINS PUMP May 25, 1937.

- 3 Sheets-Sheet 1- Original Filed 'Nov. 5, 1929 /zw- 1 0127712?! M Jib 016177.); I

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May 25, 1937.

D. N. IHAPKINS PUMP Original Filed Nov. 5, 1929 MOMMA;

May 25, 1937. D. N. HAPKINS PUMP Original Filed Nov. 5, 1929 3 Sheets-Sheet 3 Patented May 25, 1937 UNITED STATES PATENT OFFIQE PUMP Dimitri N. Hapkins, L of fifteen per cent to Angeles- County, Calif.

s Angeles, Calif., assignor Clarence L. Kincaid, Lo

404,937, November July 10, 1936, Serial 9 Claims.

This invention has reference generally to rotary pumps, compressors, superchargers and the like, and is concerned particularly with an improved pump of the rotating and oscillating piston type. It is somewhat similar to the pump disclosed in my co-pending application, Serial No. 475,983, filed August 18th, 1930. This case is a refiling of applicants application, Serial No. 404,937, filed Nov. 5, 1929 and which has become abandoned.

The characteristics of power machines, such as engines, pumps or other fluid mechanisms, of the type to which this invention belongs, are, briefly, the use of a cylindrical rotor turning within a cylindrical casing and having movable members caused to operate by an eccentric which members act as pistons either to draw in a fluid and expel it or to receive a fluid under pressure and convert the energy therein into power delivered at the shaft of the machine and about which the rotor turns. The rotor is a short cylinder flanged at each end, thereby producing a member which may be described as an endflanged cylinder or as a cylinder having a comparatively long, deep circumferential channel. Mounted in the groove or channel between the two flanged ends are spaced divisional members projecting radially outward from the middle portion of the rotor, forming separate chambers. 0 These divisional members are called abutments. A plurality of members, which cover the said chambers, are mounted on the rotor, one within each chamber, each member being supported by a pivotal stud passing through one end of the member, the two ends of the stud being carried by the two rotor flanges into which the stud ends pass. Hence, these cover members or leaves are adapted to rock or oscillate about the stud at one end, and the previously mentioned eccentric 40 means are provided to cause the free end of these leaves to move inward and outward within the chamber and thus to draw in and express a fluid. The free ends of the leaves are moved by connection with the eccentric when the rotor is turned.

The operation of the present pump, made in accordance with my invention, is such that pressure is exerted on the fluid in two stages, that is, during both the inward and outward movement of the rocking leaves, the fluid being by-passed from one surface to the other surface of the leaves during these movements. In the typical form of the invention hereinafter described, the fluid is drawn successively into each chamber as the rocking leaf is carried on the rotor past the 1929. This application inlet in the casing, at which time the free end of the leaf is moving inward.

In subsequent discussion, when the leaves are referred to as moving inward or outward, it is to be understood that this applies to the inward and outward movement of the free end, the degree of movement gradually diminishing toward the pivotal end, as is usual in any pivoted rocking device. At the limit of the inward movement of the leaf, the chamber is filled with fluid which is outside of the leaf, the latter being substantially at the bottom of the chamber. Each of the rotor abutments or divisions, forming the ends of the chambers, moves to seal the chamber after passing the inlet, by contact with the inner wall of the casing. At this point the leaf begins its outward movement and the fluid at the outside of the leaf is forced through certain transfer passages into the inner space in the chamber which is left under the leaf as it moves outward. Then, upon return movement of the leaf toward its inner position, the fluid is expressed outward through discharge passages in the casing, additional fluid being simultaneously drawn into the chamber at the outside of a leaf as before described.

An object of this invention is to providea pump of this character, of high efficiency, of large pumping capacity for any given dimensions, and capable of pumping fluids against high pressures, and of sturdy and durable construction, which can operate under diflicult conditions without appreciable wear. Hence, this invention relates more especially to the arrangement of a system .of transfer passages whereby the fluid is delivered from one side to the other of the leaves, and in the mechanical means for rocking the leaves and in automatic elimination of end thrust on the rotor. I-Ieretofore, transfer of the fluid from one side to the other of the leaves has taken place through passages or ports in the abutments and through the leaves themselves, or both. In this invention fluid passes around the leaves through passages formed in the end walls of the rotor and in the inner wall of the casing instead of through the abutments or leaves, so that these latter members are solid and of resultant maximum strength. Another object which is attained by using the solid leaves and abutments is to produce a structure in which all ports in the rotating member are confined to the rotor end flanges, so that the parts between which relative motion takes place may be easily, accurately and cheaply made. Past attempts to devise pumps of this character have resulted in machines diflicult to construct because the form of the ported parts in the rotor members which require fitting for leakless relative motion is too difiicult to manu facture and is not adapted for machining in the usual and ordinary manner. By making all ports in cylindrical flanges fitted into surrounding oylindrical members, the fitting therebetween may be done with usual shop equipment.

Also, instead of connecting each leaf with an individual eccentrically-mounted element to effect rocking movement of the leaves, as is general in mechanisms of this type, this invention provides for connecting all of the leaves with a single eccentric. Further, the customary use of intermediate links and connecting members between the eccentrics and the leaves is avoided in this invention, the plurality of leaves being directly connected with the single eccentric. Hence, the construction is both strengthened and simplified.

With the foregoing and other objects in view, the invention consists in the novel and useful formation, construction, interrelation and combination of parts, members and features, as well as mode and methods of use thereof, and steps and perfornances taken and had, all as hereinafter described, shown in the drawings and final- 1y pointed out in claims.

The above and various additional features and objects of the invention will be most readily and clearly understood from the following description of a preferred and typical embodiment thereof, reference being had throughout the description to the accompanying drawings, in which:

Fig. 1 is a medial section through the pump in a plane at right angles with the longitudinal axis thereof, as indicated on line I! of Fig. 3, the compression leaves being shown in elevation;

Fig. 2 is a reduced section, diagrammatic in parts, similar to Fig. 1 but showing a reverse relative arrangement of the rotor and the intake and exhaust passages;

Fig. 3 is a section on broken line 3-3 of Fig. 1;

Fig. 4 is a reduced: perspective view of the body of the pump rotor;

Fig. 5 is a perspective view showing one of the compression leaves or pistons;

Fig. 6 is a fragmentary section on line 66 of Fig. 1;

Fig. '7 is a left end view of Fig. 3, a portion of the cover plate being broken away to show the exhaust ports.

Fig. 8 is a fragmentary section on line 8-8 of Fig. 3 showing particularly the arrangement of the exhaust passages; and

Fig. 9 is a fragmentary section on line 9-9 of Fig. 3 illustrating the connection between the rotor end plates and the compression ring, at one of the abutments.

Referring first to Figs. 1 and 3, the pump casing comprises a cylindrical shell it having a base portion Ella and end closures H and i2 secured to shell it by screws It. A fluid inlet M, drilled in the lower portion of the shell, leads into the interior of the shell through the curved channel Way or groove 15. The size, or more strictly speaking, the length of inlet opening it, is determined by the extent of recesses I5, and for reasons that will be later understood, is predetermined in accordance with the size and spacing of certain of the rotor parts.

The rotor, generally indicated at H, preferably is made in sections comprising the end walls or plates i3 and 53, preferably having a slight taper from the inner wall of shell it as will hereinafter be explained. For purposes of construction, I prefer to form the rotor end plates with spaced concentric outer flanges 2E! and 2| between which project flanges 22 formed on the inner faces of the casing end closures H and I2. Annular flanged liners 2 3, preferably of brass or other suitable comparatively soft metal, are placed between the rotor and casing end closures at the outside of flanges '22, in order to provide a proper bearing surface for the outer portion of the rotor. The rotor is driven by way of drive shaft 25 which is connected to suitable power means, not shown, the shaft extending centrally through end closure ii of the casing, through packing gland 26, and being keyed as at 21 to the rotor end plate 58. Bearing 28, fitted between plates H and if! as indicated, serves as the drive shaft bearing and also as one of the rotor bearings, since the outer ring 28a is engaged by and partially confined within rotor flange 21.

The rotor has bearing at its other end on a stationary or dead shaft 3! carried centrally within casing end closure l2. Shaft St may be mounted in said closure in any suitable manner, and as a typical means I show the shaft to be keyed as at 3! within ring 32, Which is secured to the casing by screws 33. Gaskets 34 are placed between ring 32 and the casing to prevent outward fluid leakage around shaft 30. Rotor bearing 35 is confined between the casing and rotor end plate l9, and within annular flange 2!, similar to bearing 23.

A ring 3?, concentric with the rotor, is secured between the rotor end plates EB and I9 by means of screws 62, see Fig. 9, the heads of which are countersunk as at 3 within the end plates, the ring being seated in annular grooves 33, see Figs. 3 and 6, formed in the innerfaces of the rotor plates. Dowels 320. preferably are inserted in the abutments and rotor end plates as shown. The ring 3'1 has integral projecting portions it, in number corresponding to the number of leaves, the projections forming circularly and equally spaced abutments between the body of the ring and the inner wall llic of the cylindrical shell. The projections 58, together with the body of ring 3'5 and the inner wall lllc of the casing, define the chambers 0, within which suction and compression of the fluid takes place, as will be explained. It will be noted that the outer faces iiia of abutments M3 are substantially cylindrically shaped in conformity'with the curvature of the casing wall ltc, although they may have a slight taper in accordance with the general taper of the rotor as will be more fully described later.

The illustrated pump rotor is shown typically as having four rotor chambers C, and a swinging, or rocking leaf -55 within each chamber, the leaf being pivotally carried on shaft at extending through plates l8 and i9, the ends of which are countersunk within openings 4'! formed in the outer faces of the plates. The leaves preferably are provided with cylindrical bearings $8 of suitable material. Ends 553 of the leaves are cylindrically shaped and have a substantially sliding fit with correspondingly shaped end faces 5! on the abutments 4E9, in order to provide backing for the leaves throughout their swinging movement, and thereby insuring shafts 43 against strain. As shown in Fig. 5, the leaves are formed in duplicate half sections 45a, 455, connected together as at 52. The outer faces 53 of the leaves are circular arcs with a radius equal to that of the bore of the casing, so that when in their outermost positions the outer leaf surface conforms with the inner wall lOc of the casing. The outer, or free end of each leaf 45 is made much thicker than the rest of the leaf thereby increasing the area of the leaf at a zone where the movement is greatest and adding to the displacement for each oscillation. The two widened portions 4511 are extended angularly inward towards the centre of the rotor thereby making a yoke attached to or integral with the leaf, as shown in Fig. 5. This portion of the leaf being much thicker than the axial distance between the rotor flanges, these latter have paired radial slotsfifl arcuate in form, to admit and accommodate these widened leaf ends. By slotting the projection or arm, from its outermost end to the plane of the inner surface of the leaf, the slot centre line being coincident with the central plane through the leaf, the yoke is formed whereby the leaf is directly connected with the eccentric ring 60, so that turning of the rotor 20 causes the leaves 45 to rock inward and outward in the circumferential chambers C. As shown, all of the lateral surfaces of the yoke, or of planes therethrough, are mutually parallel, and the width of the yoke slot is substantially equal to the. width of the leaf, as indicated in Fig. 5. Both the end, or outer surface 55, and inner surface 54 of arms 450 are arcuate in form, being circular arcs whereof the centre is that of pivot 46, or of the leaf pivot holes 41, 48. As shown in Fig. 1, the curved arms 45a extend inward through slots 51 of appropriate form and dimensions in the ring 31, which latter member forms the bottom of each of the chambers, spaced around the rotor. By this construction, the narrower portions of leaves 45, spread across the distance between the inner flange surfaces and can rock smoothly in and out between the flanges l8 and I9 from casing wall We to inner ring 31, the recesses 90 accommodating the wider ends of the leaves and the yoke arms 450 in their rocking motion. This thickened leaf, giving greater displacement, and the widened yoke portion proceed from certain preferred forms and designs, one whereof is important, viz., the confining of all ports to the rotor flanges and, therefore, to an ordinary, lathe-turned surface, which is the easiest, cheapest form in any mechanism for fitting two members together for smooth and leakless relative motion. In order to provide ample stock for the ports, the flanges must be somewhat thicker than for the now discarded type in which the ports were made through the leaves and in the abutments. The excess stock in the thickened flanges at portions between ports can be made thinner over such zones. This is done by forming the paired radial arcuate slots 90, giving a considerably greater axial width across the bottoms of the slots than between the flange surfaces. This then permits widening the leaf where its movement is greatest, so that the displacement, per oscillation, or area multiplied by distance of motion, is greatly increased. This arrangement also permits adoption of thick yoke members without reduction of displacement or encroachment on any useful space, which thick members admit deep counter bores 65 large enough to receive ball bearings for the pin connections with the eccentric ring.

The central cylindrical member 30 is fastened rigidly in the end plate l2 (Fig. 3) and extends toward the vertical middle plane of the casing, its end being approximately flush with the inner surface of rotor flange l9. Attached to the end of member 30 or integral therewith is a circular member 30a, the centre whereof is not coincident with that of member 30 but is offset therefrom, thereby producing a fixed eccentric relative to the axis A--A' of the rotor. The circular cup-shaped member 60 is mounted on the outer ball-race of rotor bearing 6| while the inner race is mounted on eccentric member 30a, the member 60 being confined between the inner faces of the rotor flanges l8 and I9. spaced arcuate slots 63 are formed through the outer portion 60a of the cup-shaped, eccentric member 60, the centre of curvature of the slots being at the axial centre of the member corresponding with the centre of eccentric 30a.

The yokes of the rocking leaves fit over the eccentric ring 600; and are connected thereto by means of pins 64 extending through slots 63 and terminating within the circular recesses 65 formed in the inner faces of the yoke portions or leaf arms 450 of the leaves, the pins 64 fitting the width of the slots and permitting free movement of the pins arcuately therein. Pins 64 have their ends fastened in roller bearings 66, placed within recesses 65. The leaf arms 45c fit into the openings 51, through the periphery of ring 31.

Rotation of the rotor, with the eccentric ring, causes the leaves to move inward and outward in their respective chambers by virtue of the eccentric motion of ring 80. Pins 64 work to and fro angularly in the arcuate slots 63 in eccentric 60 as the rotor turns and the leaves move in and out, this motion in the slots 63 being a component of the rocking motion about fixed pivots 46.

Having described the manner in which the compression leaves are caused to move inward and outward in chambers C as the rotor is caused to revolve, I will now describe the system of ports and passages whereby the fluid is transferred from one side to the other of the leaves and then finally exhausted to the pump discharge. Transfer of the fluid from the outside to the inside of the leaves occurs by way of a channel l formed in the interior wall of the casing, the channel being somewhat wider than the chambers C, see Fig. 6, and extending part way around the rotor, as will be more fully explained later. Communication between channel is and spaces S in the chambers at the inside of the leaves, occurs 'by way of ports H and 12 formed in rotor end plates I8 and I9 at each side of the chambers. Thus during the interval of the rotor travel in which the chambers C are opened to channel 10, the fluid flow occurs as indicated by the arrows in Fig. 6, that is. the fluid is forced by the leaves into channel 10, and then through ports H and 12 into the chamber at the inside of the leaves.

As shown particularly in Figs. 3 and 8, exhaust passages 15 are formed in the casing end closures II and I2, these passages having consider able circular extent as indicated, and opening at the outer face of flanges 22 into ports 16, of similar extent, formed in the liners 24. As the rotor revolves. ports 16 are adapted to register with ports 1'! formed in the rotor end plates opposite ports 12, and opening at the inner faces of flanges 20. As ports '16 and T! are brought into registration, the fluid within the chamber at the in- Equally side of the leaves is forced by the latter during its inward movement, through ports l2, ll, i6 and exhaust passages 75. On each end of the rotor casing is a cover plate I3, secured thereto by screws '59, and having integral discharge conduits 8H communicating with passages by way of openings 8| in registration with said passages. Thus it will be seen that the fluid in the chambers is forced outward at opposite sides thereof into passages 15, and thence conducted through the cover plate openings 8! into the two discharge conduits 39.

The operation of the pump through one cycle, or revolution, of the rotor, and assuming the rotor to turn in the direction indicated by arrow R in Fig. 1, is as follows: The position of the eccentric 6!! is such that when a leaf travels past the inlet it is caused to move inward, and thereby to draw the fluid into space S in the chamber outside of the leaf. After the leaf travels past the inlet opening, and the abutment Ml, adjacent the pivoted end of the leaf, reaches a position at which it seals the chamber from the inlet, as indicated at 892), the leaf having swung to the chamber bottom starts its outward movement, which movement uncovers ports '32 and forces the fluid into channel it] and through ports ll and 12 into the chamber at the inner side of the leaf as described, this expressing and transferring of the fluid taking place throughout the outward movement of the leaf. During outward movement, the chambers are in communication with channel '50, and the fluid is forced into spaces S between the ring 3? and the leaf.

At the point at which the leaf reaches its outermost position, it has substantially moved past the end 76a of channel it and against the casing as at Ma. At this point, and at which the leaf starts its inward movement, ports I! at the sides thereof are brought to register with ports l8, and remain in registration with ports it throughout the inward travel of the leaf. During this interval, the fluid is discharged from space S into passages 15 and into discharge conduits to as previously mentioned. From the foregoing it will be apparent that the extent of channel 'lfl and the extent of ports it are predetermined in accordance with the periods of fluid transfer in the compression chambers from the outside to the inside of the leaves, and with the period of discharge, respectively.

It will be noted that the space S in the compression chambers between the inner ring 3? and the inner face of the leaf, when the latter is in its outermost position, is of comparatively less volume than space S between the outer face of the leaf and the casing, when the leaf is in its innermost position. Thus as the fluid is forced from space S to space S, and then expelled from the latter space as the leaf moves inward, a two stage movement of the fluid takes place. It will also be seen that by the provision of a common transfer passage H3 through which the fluid from each of the chambers in communication therewith is conducted during outward movement of the leaves, and by the provision of a substantially continuous exhaust port it into which exhaust from those chambers in communication therewith occurs simultaneously, the pump is enabled to operate with smooth and non-pulsating action.

The capacity of a pump of given size may be predetermined in accordance with the size or proportioning of the rocking leaves. The shape, width and thickness W of the leaves may be changed to vary the capacities of the chambers and, therefore, the capacity of the pump. Thus, for example, the capacity of the pump illustrated could be increased by substituting thinner leaves and adjusting the eccentric to move them inward and outward to the same limits as the thicker leaves shown. This change would increase the volume of each chamber by an amount equal to the circumferential area of the chamber multiplied by the diminution in thickness, as is obvious. The shape and size of the leaves may thus be varied in numerous ways to accord with the conditions desired.

Due to fluid leakage around the yoke portions 5 3 of the leaves, space 92 within the ring 31 is filled with the fluid being pumped. If the fluid is a lubricant, that contained within space 92 serves to lubricate the eccentric bearing 6|. In pumping non-lubricating fluids, however,,, special means for lubricating the eccentric bearing are required. As typical of such means, I have shown radial passages 93, drilled in the opposite portion 33a of the stationary shaft, 30, communicating with passages 96 formed in the inner bearing ring, and supplied with lubricant from cup 925 and bore 9'! drilled in the shaft.

In order to limit the maximum pressure developed in the pump, it may be desirable to provide a safety valve, diagrammatically shown at 85, in line a, leading through the casing shell from channel ill.

I have shown the rotor end plates to be tapered, as at T, somewhat toward one end and away from the drive shaft, the degree of taper being exaggerated as shown, for purposes of illustration. The outer face of the abutments and leaves are likewise shaped in accordance with the taper of the rotor plates. A particular advantage is gained by so tapering the rotor, in providing space for a liquid cushion or film about the rotor which serves to minimize friction within the casing and to reduce the thrust on the bearings. Due to the rotor being tapered in a direction away from the drive end, end thrust on the rotor in that direction is resisted by the liquid confined in the clearance space between the rotor and casing, thereby greatly relieving the bearings of end thrust.

Although I have described the pump assuming the rotor to be revolved in the direction of arrow R, it will be understood that the pump may operate by rotation of the rotor in an opposite direction, by reversing the rotor within the casing and adjusting the position of the eccentric accordingly. And it may be mentioned that any suitable provision may be made for so rendering the eccentric adjustable. In Fig. 6 I have illustrated the relative arrangement of the rotor parts, the eccentric, and the intake and discharge passages for rotation of the rotor in the direction of arrow R, opposite to that shown in Fig. 1. In this case, the eccentric is so adjusted that the leaves start their inward movement at the left of intake l6, completing their inward movement during the course of their travel past the inlet, and then start their reverse outward movement as the chambers are brought into communication with the end ltlb of channel Til, outward movement of the leaves continuing throughout their travel past said channel. By causing the rotor to revolve as indicated in Fig. 2, an additional advantage is gained due to the action of the curved faces 5th of the abutments on the liquid at the inlet. As the abutments move past the inlet, faces Eilb have somewhat of a scooping action, tending to drive the fluid inwardly within the chambers, as distinguished from the action in Fig. 1 wherein the fluid is drawn into the chambers by'suction alone.

From the foregoing description it is seen that this pump is designed to have the rotor turn through more than 360 degrees from the beginning of intake to completion of discharge, the angular distance of rotation from beginning of intake to beginning of discharge being, in practice, about 270 degrees. Also from beginning of discharge until its completion the rotation is approximately 180 degrees, the total angular distance traversed from beginning of intake until completion of discharge being usually over 400 and as much as 450 degrees. However, as both sides of the rocking leaves are used, the cycles of intake, transfer and discharge overlap, and the operation is not limited to one cycle only for 400 or more degrees. This pump, therefore, differs from the rotor and leaf pumps which move the leaves inward to draw in the liquid and immediately thereafter begin outward movement of the leaves to discharge. The benefits derived from a comparatively long travel of any single rotor chamber for a complete cycle, are obvious. The pressure of the liquid between the rotor and casing is kept down to some small value not much exceeding atmospheric, until beginning of the first outward movement of the leaves to move the fluid from outside to inside of the leaves. This movement being produced within a-comparatively long distance of motion, a low pressure will drive the fluid through even small ports within the time of about half a revolution. Hence, no high pressure exists anywhere or at any time between the casing and the rotor peripheries. High discharge pressure can exist only between the inner face of the blade and the annulus, forming the bottom of each rotor chamber. Therefore, no pressure sufficient to cause leakage can exist around the rotor at any peripheral point or zone. If any leakage occurs it must be limited to the side walls of the chambers or in the running fit between the flanged rotor ends and the casing ends, but since these end pressures mutually balance, the friction loss therefrom is small. Furthermore, by keeping the peripheral pressure always low, the frictional resistance to turning of the rotor is likewise kept low. Also, it is obvious that the comparatively.

long time, both of intake and of discharge, permits the use of comparatively small ports, so that the design of the machine may be made compact and quite difierent in many respects from the ordinary form of rocking leaf pump in which intake is immediately succeeded by discharge.

It will be understood the drawings and description are to be considered merely as illustrative of and not restrictive on the broader claims appended hereto, for various changes in design, structure and arrangement may be made without departing from the spirit and scope of said claims.

Having thus disclosed my invention, I claim and desire to secure by Letters Patent:

1. In a mechanism of the character described, a cylindrical casing having inlet and discharge openings; a cylindrically shaped rotor within the casing, said rotor embodying a pair of spaced tapered end plates, a pair of circularly spaced abutments forming a chamber therebetween, and a rocking compression member in said chamber, means for rocking said member inward and outward upon rotation of the rotor, and a passage in said casing for transferring fluid in said chamber from one side to the other of said rocking member.

2. In a pump of the character described, the combination of a cylindrical casing having an intake opening, a rotor mounted in the casing and having a plurality of circumferential chambers therearound, a solid fluid-moving leaf in each chamber and having ports, the rotor having passages extending from said chambers through the rotor ends, each leaf being pivotally mounted at one end on the rotor, means for rocking said leaves about said pivotally held ends, the casing having a by-pass channel and fixed ports adapted to successively register with said rotor ports, said by-pass channel being adapted to transmit fluid from the outer to the inner face of said leaves, there being two ports opening into each chamber through opposite ends thereof, respectively, said rocking means comprising a single eccentric connected directly to all of said leaves by pins common to the eccentric and the leaves.

3. In a pump of the character described, the combination of a cylindrical casing having an intake opening, a rotor mounted in the casing and having a plurality of circumferential chambers therearound, a solid fluid-moving leaf in each chamber and having ports, rotor passages extending from said chambers through the rotor ends, each leaf being pivotally mounted at one end on the rotor, means for rocking said leaves about said pivotally held ends, the casing having a by-pass channel and fixed ports adapted to successively register with said rotor ports, said by-pass channel being adapted to transmit fluid from the outer to the inner face of said leaves, there being two ports opening into each chamber through opposite ends thereof, respectively, said rocking means comprising a single eccentric connected directly to all of said leaves by pins common to the eccentric and the leaves, and means for automatically balancing the axial thrust on said rotor comprising the provision of a discharge opening at each end of the casing cooperating with two oppositely placed chamber ports.

4. In a pump of the character described, the combination of a cylindrical casing having ends and an intake opening and a pair of opposed outlet openings in the ends, a rotor mounted in the casing and having a plurality of circumferential chambers therearound, a solid fluid-moving leaf in each chamber pivotally mounted at one end on the rotor, said rotor having ports in its ends, and the casing having a partly circumferential channel whereby fluid is transferred from one side to the other of said leaves, means for rocking said leaves inward and outward on the rotor, the leaves and rocking means being directly connected together, said two outlet openings communicating each with a channel in the casing end, said channels being positioned to register with ports in the rotor and form a continuous path from the rotor to an exhaust opening for discharge of fluid during rotation of the rotor while said leaf is moving inward.

5. In a mechanism of the character described, the combination of a cylindrical casing having fluid openings therethrough, a rotor mounted in the casing and having a plurality of circumferential chambers thereon, a solid fluid-moving leaf in each chamber pivotally mounted on the rotor and having integral projecting yokes, an eccentric, an eccentric ring thereon having a peripheral thickness to mate with said yokes,

means for directly connecting all of said yokes to the eccentric ring comprising a single pin common to a yoke and the ring, and automatic means for axially balancing the discharge pressures on the rotor, comprising a pair of oppositely end-positioned discharge openings formed through said casing.

6. In a mechanism of the character described, the combination of a cylindrical casing having a fluid intake opening and a pair of oppositely located discharge openings therethrough, a rotor mounted in the casing and having a plurality of circumferential chambers thereon and ports through the ends thereof, a solid fluid-moving leaf in each chamber pivotally mounted on the rotor and having integral projecting yokes, an eccentric, an eccentric ring thereon having a peripheral thickness to mate with said yokes, means for directly connecting all of said yokes to the eccentric ring comprising a single pin common to a yoke and the ring, each of said discharge openings merging with an arcuate chan nel extending partly around the rotor axis and having a radius substantially equal to that of a rotor port wherethrough fluid within a chamber is forced out through the discharge opening during the rotation of the rotor when said port and channel register and said leaf is moved inward.

7. In a mechanism of the character described, a casing having fluid passages therethrough, a rotor having flanged ends with ports therethrough, a plurality of circumferential chambers between the flanges, a solid fluid-impelling leaf mounted to rock about one end in each chamber, a single means to oscillate all of said leaves, including an eccentric ring having an arcuate slot adjacent the periphery for each of said leaves, and a direct connection of each leaf to said ring comprising a pin passing through one of said slots and through the end of a leaf mating therewith.

8. In a mechanism of the character described,

a casing having fluid passages therethrough, a rotor having flanged ends with ports therethrough, a plurality of circumferential chambers between the flanges, a solid fluid-impelling leaf mounted to rock about one end in each chamber, a single means to oscillate all of said leaves, including an eccentric ring having an arcuate slot adjacent the periphery for each of said leaves, and a direct connection of each leaf to said ring comprising a pin passing through one of said slots and through the end of a leaf mating therewith, said leaves being thickened at the oscillating end for added displacement, there being paired radial channels in the rotor flanges to accommodate the thickened portions of the leaves.

9. In a mechanism of the character described, a casing having an intake and discharge openings, a rotor within the casing, flanged at each end and carrying a pair of circularly spaced solid abutments forming a chamber between the flanges, a solid pivotally-mounted member between said flanges in each chamber, means for rocking said member inwardly and outwardly in said chamber upon rotation of the rotor, means for transferring fluid within a chamber around said member from one side to the opposite side thereof during its rocking movement, means for admitting fluid to the chamber when said member moves in one direction, and means for expelling Q the fluid when the member moves in the opposite direction, said means including ports formed in the flanges of the rotor, the casing having an interior peripheral channel partly encircling the each end thereof, said channel being positioned to register with said rotor flange ports when said leaves are being moved outward, and said discharge ports being positioned to register with rotor flange ports when the leaves are being moved inward for the purposes described.

DIMITRI N. HAPKINS.

rotor, and the casing having a discharge port in 

